TextWrangler – a free, but powerful, plain text editor that has syntax support for HTML. Also includes a powerful RegEx (Grep) find and replace tool.
BlueGriffon – a free, but powerful, WYSIWYG content editor powered by Gecko, the rendering engine of Firefox. It has very powerful and easy-to-use table design/layout/editing, and WYSIWYG setting of CSS and form element properties. It also has direct HTML code editing.
Wiki editors: please add HTML editors you have found that work well.
TextWrangler has become BBEdit.
Beside BBEdit, I also use Atom, Brackets, and Visual Studio Code. All are free. I usually use different editors for different projects, so that when I open a certain editor, it opens that project by default. I don't have to switch between different projects. For instance,
Atom is linked with the Github server to sync a html website hosted there,
Brackets is linked with a ftp server to sync some coded files there,
VSC is mainly used for the Custom HTML Prompt files which are stored locally, and
BBEdit is used for a string translation project and as a temporary txt file editor (it's fast to launch and it has a separate search window).
When BBEdit went commercial Bare Bones Software decided they wanted to offer a free version of BBEdit, and BBEdit Lite was born.
BBEdit Lite was discontinued in 2003, and the commercial product TextWrangler was introduced as a lower cost and lower featured alternative to BBEdit. It didn't fly for very long and became freeware as of version 2.0.
TextWrangler stood in place of BBEdit Lite for many years, but development was discontinued in 2017 after a Litemode was added to BBEdit.
BBEdit's demo period is 30 days, and if not licensed at that point it becomes BBEdit-Lite (freeware). Many of BBEdit's sophisticated functions are lost, but BBEdit-Lite is still very powerful and useful for anyone who works with text.
I've used BBEdit for almost 30 years now, and it runs on my systems 24/7.
I'm concerned to see it hasn't been updated since Oct 2019 though. With a price tag of $80.00 USD I'm not buying a copy any time soon. The demo period would appear to be open-ended, so it might be worth looking at if you have a need.
Sublime Text may be downloaded and evaluated for free, however a license must be purchased for continued use. There is currently no enforced time limit for the evaluation.
UltraEdit (commercial) Expensive – $80.00 USD / Year subscription.
Jedit Ω (commercial) – An excellent, scriptable Rich Text / Plain Text Editor – about $18.00 USD.
These are all I can think of off the top of my head.